1. Field of the Invention
The present invention relates to a deflash technique for removing flash from a portion of a semiconductor package to be plated before a plating process and after a sealing process accompanied by resin molding during the manufacture of semiconductors, and more particularly to a semiconductor package having grooves formed at side flash, a groove forming method, and a deflashing method using the semiconductor package, for removing the side flash formed at a side portion of a lead frame where it is difficult to perform a deflashing process.
2. Description of the Related Art
Generally, existing semiconductor manufacturing processes include a deflashing process in order to remove flash from a semiconductor package. Examples of a well known deflashing process include a deflashing process using high-pressure injection of water jet or other media, and a deflashing process using laser irradiation.
As shown in FIG. 1, on the semiconductor package, designated as reference numeral 1, flash 3 generated during a sealing process accompanied by resin molding is partially attached as impurities at a lead frame 10 near sealing units 12. The flash 3 has to be removed according to the above mentioned deflashing process using the high-pressure injection of water jet or other media, in order to enable a subsequent plating process to be successfully performed. FIGS. 2 and 3 show a state before the deflashing process and a state after the deflashing process, respectively.
Even after the deflashing process using the high-pressure injection of water jet or other media is performed, however, as shown in FIG. 3, side flash 30 is still attached to and remains at corner regions between the sealing units 12 and lead units 14, and cannot be easily removed therefrom. Currently, such side flash is a very difficult problem hard to solve in a deflash technique field.
Although it may seen reasonable to solve the above problem by raising an injection pressure of the water jet or other media so as to improve the removal efficiency of the side flash 30, this solution is undesirable since, when the water jet or other media is injected at a very high pressure over a predetermined appropriate pressure, various negative effects including damage of the sealing units 12 or lead units 14 are caused. Further, in order to inject the water jet or other media at the very high pressure, it is necessary to install supplementary facilities including a pump and the like so as to satisfy requirements of the very high injection pressure, and to overcome various technical difficulties additionally caused by the supplementary facilities. In fact, therefore, it is difficult to apply this solution.
Another deflashing process using laser irradiation is utilized to remove flash, which is attached to the surface of a heat sink usually made of metal during a sealing process in the manufacture of a semiconductor package having the heat sink thereon. The deflashing process using laser irradiation, however, is somewhat troublesome and causes deterioration of deflashing efficiency since the area of the heat sink is relatively large and laser beams must be uniformly irradiated over the whole surface of the heat sink. Further, the laser beams may be accidentally irradiated onto the sealing units in addition to the heat sink, resulting in damage to the sealing units. Therefore, the deflashing process using laser irradiation is unsuitable to be applied so as to directly remove side flash.
Due to the fact that impurities attached on the surface of the heat sink have various shapes and thicknesses, the laser beams must be irradiated at various strengths as occasion demands, but this is not easily accomplished. Therefore, there is a difficulty in practical use of the deflashing process using laser irradiation. For these reasons, currently, the previously mentioned deflashing process using the high-pressure injection of water jet or other media is mainly used.